A recently filed patent (Ser. No. 12/954,704) described a new type of electric fence: transmission line based electric fence. This type of fence has a distinctive advantage over conventional fences: it can locate an intrusion.
Since transmission lines have attenuation, the working distance of this type of electric fences has a limited range. To extend the working distance range, electric signal repeaters are highly desirable. The basic functionality of an electric repeater is to amplify electric signal, and particularly, short electric pulses in transmission line based electric fences. Due to the nature of this type of electric fences, the repeater needs to amplify signals traveling in both directions without introducing interference between the signals in opposite directions.
It is common practice to design and build amplifiers for amplifying signals in one direction. It is difficult, however, to design an amplifier that can amplify signals in opposite directions.